1. Field of the Invention
The present invention relates generally to a plastic mold decapsuling apparatus and more specifically to a plastic mold sample holder incorporated in the decapsuling apparatus. The apparatus can dissolve a joint surface of a plastic mold or resin capsuled device such as semiconductor chip, capacitor, hybrid integrated circuit, etc. in order to inspect causes of detectiveness of the device.
2. Description of the Prior Art
In the conventional plastic mold decapsuling apparatus, a plastic mold device sample is usually mounted on a sample holder upside down and depressed onto the sample holder by a socket or a sample push bar, so that the plastic mold sample will not be moved or disclosed when an etchant is jetted to the sample for decapsuling treatment.
In the prior-art plastic mold sample holder of the decapsuling apparatus, however, since the device sample to be decapsuled is only pushed down, when the device sample is partialy broken or damaged, there exists a problem in that air is readily introduced into the etchant chamber formed in the sampled holder so that etchant jetting pressure is decreased when etchant is supplied under pressure or increased when etchant is supplied under vacuum (negative pressure). Once the etchant pressure changes, since etchant cannot be supplied sufficiently, it is impossible to effectively perform a reliable decapsuling treatment.
Further, when a large integrated circuit is embedded within a plastic mold, since the mold device sample must be decapsuled completely, there exists a problem in that air is also readily introduced into the etchant chamber formed in sample holder and therefore it is also impossible to continue a reliable etchant treatment.
Further, in case a device sample is decapsuled at a little dislocated position, it is necessary to decapsule again the same device sample. In this case, there exists a problem in that air is also introduced into the etchant chamber from outside, so that it is impossible to further decapsule the device sample.
Further, when the plastic mold sample is spherical in shape, air is easily introduced into the etchant chamber and therefore reliable decapsuling treatment is disabled.
Furthermore, when a plastic mold device sample is being decapsuled, plastic broken pieces are often produced or separated from the sample. Therefore, there exists another problem in that the etchant supply passage and/or the waste etchant discharge passage are clogged by separated plastic mold pieces.